Many people believe that drinking grape juice prevents stomach flu. However, reports of this are anecdotal and there is no scientific evidence to support this belief.

Stomach flu is a broad term covering different infections that cause vomiting, abdominal cramps, and diarrhea.

The Centers for Disease Control and Prevention (CDC) identify norovirus as the leading cause of stomach flu in the United States, estimating that 19–21 million people contract the virus each year.

The CDC also recommends that people with stomach flu drink plenty of liquids to prevent dehydration. People with stomach flu may be able to drink grape juice to replenish fluids if they can keep it down.

In this article, we will explore why people think grape juice may help prevent stomach flu and what scientists know about the health benefits of grape juice. We will also detail the scientifically recommended ways of preventing stomach viruses.

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Some people believe that drinking grape juice protects them against stomach viruses.

Popular theories argue that the drink alters the pH of the stomach and that the increased acidity stops the virus from multiplying.

Others suggest that the juice has antiviral properties. But scientists have yet to prove a link between grape juice consumption and stomach flu prevention.

The origins of these beliefs may lie in what scientists know about grapes.

A study published in the journal Nutrients suggests that taking a grape powder supplement can increase gut microbiome diversity, which may promote good health. The powder contains the equivalent of two servings of grapes or around 100 milliliters of grape juice.

An article published in the American Society for Microbiology’s ASM Journals looks into how differences in people’s gut microbiomes could influence the severity of symptoms for people with norovirus infections. The article states that the microbiome could help explain why some people can resist the infection and others are asymptomatic.

However, the authors recognize that their study is the first to collect data on the composition of gut microbiomes and norovirus infections and that they need to conduct further research. They also note that this was a small study, covering just one strain of norovirus.

Grapes and grape juices are also high in vitamin C. The National Institutes of Health (NIH) explains that vitamin C boosts the immune system, helping us fight off illness.

Additionally, an article published in the Annals of the New York Academy of Sciences highlights the role of the antioxidant resveratrol in promoting general good health. Resveratrol, which is present in grapes, plays a part in heart health and may offer some protection against aging-associated conditions.

A 2015 study published in the journal Food Control reports that resveratrol may interfere with the early stages of norovirus infection. However, this study used surrogate noroviruses that affect cats and mice.

Scientists are calling for further studies to see if there is a link between grape juice and stomach flu.

Adopting a healthy lifestyle, taking plenty of exercise, and eating healthy food can help boost a person’s immune system and may help them fight off infections.

According to a 2020 report by the Produce for Better Health Foundation, people are eating fruit and vegetables less often than they used to. It notes that there has been a 15% reduction in fruit juice consumption since 2004.

People can drink grape juice as part of a healthy diet. The Dietary Guidelines for Americans, 2020–2025 recommends drinking unsweetened, 100% fruit juice to increase a person’s consumption of fruit. However, they advise that at least half of the fruit in the diet should be whole fruit rather than juices.

Preventing stomach flu from spreading

Stomach flu, or viral gastroenteritis, is a highly contagious illness that spreads easily.

The CDC explains that people can catch it from someone who already has the infection or by touching contaminated surfaces, then touching the mouth. Consuming food or drinks that a person with stomach flu has prepared can also cause someone to develop the illness.

The CDC warns that active norovirus can be in a person’s vomit or feces before they even think they are sick and can remain in a person’s intestines for over 2 weeks after symptoms subside.

It advocates sticking to a proper hand hygiene regime at all times. This includes washing the hands regularly with soap and water and being extra careful after using the toilet or changing a diaper, before preparing food or eating, and before taking any medication.

People should wash all fruit and vegetables before preparing them and make sure to cook all shellfish properly. The CDC explains that norovirus is resistant to heat and can survive temperatures of 145ºF. A person must not prepare food for other people while they have norovirus or stomach flu symptoms.

The CDC also recommends keeping surfaces clean and disinfected as part of regular household cleaning.

If someone has stomach flu and is experiencing sickness and diarrhea, the CDC suggests a thorough cleanup immediately. Wipe the entire area with a bleach-based cleaner and leave it for at least 5 minutes. Then wash with soap and hot water.

People need to regularly wash any bed linen or clothes the person with stomach flu uses at the hottest temperature the fabric allows. People should wash these immediately if they come into contact with any vomit or feces.

The CDC acknowledges that there are no specific medicines to treat stomach flu and recommends drinking lots of liquids to replace those lost through vomiting or diarrhea, as dehydration can lead to more serious problems.

If a person with stomach flu can drink grape juice, this can provide a useful boost of vitamins and minerals along with the liquid. Diluting the juice with water may make it more palatable.

According to the CDC, most people with stomach flu get better within 1–3 days.

There is no scientific link between drinking grape juice and preventing stomach flu and stomach viruses.

However, grape juice does contain many compounds that may improve the diversity of the gut microbiomes, help heart health, and prevent some illnesses associated with aging.

An article published in the Journal of Food Science acknowledges that many people in America do not meet the daily recommended amounts of fruit and vegetables in their diet. The article also states that drinking 100% fruit juice with no added sugar contributes to positive health outcomes, including improved immune health.